From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754438AbYJAQMs (ORCPT ); Wed, 1 Oct 2008 12:12:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753244AbYJAQMY (ORCPT ); Wed, 1 Oct 2008 12:12:24 -0400 Received: from smtp.polymtl.ca ([132.207.4.11]:38238 "EHLO smtp.polymtl.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbYJAQMX (ORCPT ); Wed, 1 Oct 2008 12:12:23 -0400 Message-Id: <20081001160425.419297059@polymtl.ca> References: <20081001160324.889716972@polymtl.ca> User-Agent: quilt/0.46-1 Date: Wed, 01 Oct 2008 12:03:28 -0400 From: Mathieu Desnoyers To: Ingo Molnar , linux-kernel@vger.kernel.org Cc: Mathieu Desnoyers , Rusty Russell , akpm@linux-foundation.org, "Frank Ch. Eigler" Subject: [patch 4/5] Markers : documentation fix teardown Content-Disposition: inline; filename=markers-documentation-probe-teardown.patch X-Poly-FromMTA: (test.casi.polymtl.ca [132.207.72.60]) at Wed, 1 Oct 2008 16:10:56 +0000 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Document the need for a marker_synchronize_unregister() before the end of exit() to make sure every probe callers have exited the non preemptible section and thus are not executing the probe code anymore. Signed-off-by: Mathieu Desnoyers CC: Ingo Molnar CC: Rusty Russell CC: akpm@linux-foundation.org CC: "Frank Ch. Eigler" --- Documentation/markers.txt | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) Index: linux-2.6-lttng/Documentation/markers.txt =================================================================== --- linux-2.6-lttng.orig/Documentation/markers.txt 2008-07-31 09:11:13.000000000 -0400 +++ linux-2.6-lttng/Documentation/markers.txt 2008-07-31 09:20:57.000000000 -0400 @@ -50,10 +50,12 @@ Connecting a function (probe) to a marke to call) for the specific marker through marker_probe_register() and can be activated by calling marker_arm(). Marker deactivation can be done by calling marker_disarm() as many times as marker_arm() has been called. Removing a probe -is done through marker_probe_unregister(); it will disarm the probe and make -sure there is no caller left using the probe when it returns. Probe removal is -preempt-safe because preemption is disabled around the probe call. See the -"Probe example" section below for a sample probe module. +is done through marker_probe_unregister(); it will disarm the probe. +marker_synchronize_unregister() must be called before the end of the module exit +function to make sure there is no caller left using the probe. This, and the +fact that preemption is disabled around the probe call, make sure that probe +removal and module unload are safe. See the "Probe example" section below for a +sample probe module. The marker mechanism supports inserting multiple instances of the same marker. Markers can be put in inline functions, inlined static functions, and -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68